Despite sharing a common neurochemical pathway, the relationship between sleep disturbances and preterm labor has not been investigated. This prospective descriptive study will compare the sleep characteristics of a group of pregnant women at risk for developing preterm with a group of normal risk pregnant women. Measurements of both groups of subjects will be made at 27 +/- 2 weeks gestation using valid, reliable tools that measure subjectively, the quality of nocturnal sleep, daytime sleepiness, and perceived stress. In addition, delivery outcomes data will be collected in order to compare sleep characteristics between those who deliver at less than 37 weeks and those who deliver at term. The results of this work will provide valuable data concerning the relationship between sleep and preterm labor and will potentially allow for the development of population-specific interventions that will ultimately improve the health of mothers and their infants.